1. Field of the Invention
The present invention relates to a spring retainer used to support a coil spring such as a valve spring and to a spring system incorporating a coil spring.
2. Description of Related Art
Among spring retainers used to support valve springs, Patent Document 1 shows a configuration that supports a valve spring with double springs.
This technique relates to a valve rotator for an internal combustion engine with a rotator body having a disc spring and a coil spring which is a circumferential garter spring. The garter spring is received in a groove of the rotator body and is in contact with a top surface of the disk spring. A bottom surface of the disk spring contacts and supports the valve spring.
When the disk spring upwardly deflects, it pushes and inclines the garter spring in a circumferential direction. According to the inclination, the rotator body turns around a valve axis to forcibly turn the valve.
According to such a structure, however, the disk spring and garter spring must have lower spring constants than the valve spring. This results in lowering an overall spring constant to limit reductions of the set height and mass of the valve spring.
Patent Document 1: Japanese Unexamined Patent Application Publication No. H08-180308